"Air pollution episode" means a situation which is declared by responsible authorities as set forth in this chapter when weather or air pollution conditions or both indicate a potential threat to human health.
"Soiling index" means a measure of the soiling properties of suspended particles in air determined by drawing a measured volume of air through a known area of Whatman No. 4 filter paper for a measured period of time (normally two hours) expressed by COH's/1000 linear feet.
9 Va. Admin. Code § 5-70-20
Statutory Authority
§§ 10.1-1307 and 10.1-1308 of the Code of Virginia.